MS-DOS:2.11:Kaypro 16 OEM/Autoload/disk02/TEXTP.FOR
Fortran program used to interact with the Text Protocol than can be used in MITE program. File content C C TEXTP - The Text Protocol C C This program is designed to run on a mainframe or minicomputer C and interact with the TEXT protocol in the MITE data communications C package. The protocol allows verified transmission of data into C environments that ordinarily are unable to perform verified transfers C of information. C C Because of the extreme variety of systems on which this program C may be implemented, this program is only a starting point. The C checksum routine will need extensive modification if the mainframe C is not using ASCII representations. The input/output will need to be C modified in most instances. What this program is intended to be is C complete documentation for the mainframe side of the protocol and an C aid in implementing a version in a specific environment. C C This version of TEXTP is written in Microsoft Fortran under CP/M-80. C C Developed October 1983 by: C C Donald Waldo C Mycroft Labs, Inc. C P.O. 6045 C Tallahassee, FL C 32314 C byte ifn(11) 5 write(1,10) 10 format(' Send (1) or Receive (2)?') read(1,15)iopt 15 format(i1) if((iopt.ne.1).and.(iopt.ne.2)) goto 5 write(1,20) 20 format(' Enter Filename') read(1,25)ifn 25 format(11a1) call open(5,ifn,0) if(iopt.eq.1)call send if(iopt.eq.2)call recv endfile 5 goto 5 end C C C C C Text file protocol - Receive C C This subroutine receives a file using the TEXT C file protocol. C subroutine recv integer*4 n,ick1,ick2,icksum,iconv,ick3 byte line(150) data iE/69/ iA/65/ iN/78/ iX/88/ C C Initialize expected message number C msgnum=0 C C Main loop - read lines and verify them. C Each line transmitted by MITE starts with a 'D'. This is followed C by a 1 digit message number which helps improve error detection. C Following the message number is a 3 digit count of the number of C data characters on the line. This is followed by a 5 digit (16 bit) C checksum. The checksum is a 16 bit sum of all characters on C the line not including the checksum itself. It is computed C by summing the ASCII representation of the characters and C ignoring overflow. The checksum is followed by the data characters. C 30 read(1,12)line 12 format(150a1) C C All done if 1st char = 'E' C if(line(1).eq.iE) goto 900 C C Aborted if 1st char = 'X' C if(line(1).eq.iX) goto 900 C C Get no. chars on line C n=iconv(line,3,3) if(n.lt.0) goto 40 C C compute checksum and verify against received value C ick1=iconv(line,6,5) if(ick1.lt.0) goto 40 ick2=icksum(line,1,5) j=n ick3=icksum(line,11,j) ick2=ick2+ick3 if(ick2.ne.ick1) goto 40 C C Verify message number C ick3=iconv(line,2,1) msg=ick3 if(msg.eq.msgnum)goto 34 if(msg.eq.msgnum-1)goto 36 if((msgnum.eq.0).and.(msg.eq.9)) goto 36 goto 50 C C Line is good. Write to disk and acknowlege. C 34 k=n+11 write(5,35)(line(i),i=11,k) 35 format(150a1) msgnum=msgnum+1 if(msgnum.eq.10)msgnum=0 36 write(1,37) 37 format(3h RA/) goto 30 C C Something went wrong. Request that the line be retransmitted. 40 write(1,42) 42 format(3h RN/) goto 30 C C Error - abort transmission C 50 write(1,52) 52 format(3h RX/) C C Transmission complete. C 900 return end C C C C C subroutine send C C Text file protocol send. C C The data lines sent to MITE follow the same format described above. C integer*4 icnt,ichk,iconv,icksum byte line(80),line2(80) data izero/48/ iblank/32/ iA/65/ iD/68/ iN/78/ iX/88/ C C Wait for OK from micro before sending first line. C read(1,20)line msgnum=-1 C C Get line from file C 15 read(5,20,end=50)line 20 format(80a1) C C Increment message number, but keep in range 0-9 C msgnum=msgnum+1 if(msgnum.eq.10)msgnum=0 C C determine count C i=80 24 if((line(i).ne.iblank).or.(i.eq.0)) goto 30 i=i-1 goto 24 30 icnt=i C C Blank-fill output buffer C do 32 i=1,80 32 line2(i)=iblank C C compute checksum C line2(1)=iD line2(2)=msgnum+izero call putnum(icnt,line2,3,3) j=10+icnt do 35 i=11,j 35 line2(i)=line(i-10) j=icnt+5 ichk=icksum(line2,1,5) ichk=ichk+icksum(line2,11,icnt) call putnum(ichk,line2,6,5) 40 write(1,45)line2 45 format(1X,80a1/) C C Get ack or nak C read(1,20)line if(line(2).eq.iN) goto 40 if(line(2).eq.iX) goto 60 if(line(2).ne.iA) goto 60 goto 15 50 write(1,55) 55 format(2h E) return 60 write(1,65) 65 format(2h X) return end C C C subroutine putnum(num,ibuf,ist,ilen) integer*4 ipwr,num,itemp byte ibuf(150) data izero/48/ iptr=ist itemp=num ipwr=1 j=ilen-1 do 5 i=1,j 5 ipwr=ipwr*10 10 j=itemp/ipwr ibuf(iptr)=j+izero itemp=itemp-j*ipwr ipwr=ipwr/10 iptr=iptr+1 if(iptr.lt.ist+ilen)goto 10 return end C C C integer*4 function icksum(ibuf,ist,len) byte ibuf(150) integer*4 k,maxint C C This function computes a checksum as described above. C maxint=2**16-1 k=0 j=ist+len-1 do 10 i=ist,j k=k+ibuf(i) if(k.gt.maxint)k=k-maxint-1 10 continue icksum=k return end C C C integer*4 function iconv(ibuf,ist,len) byte ibuf(150) data izero/48/ iblank/32/ ipw=10**(len-1) k=0 j=ist+len-1 do 10 i=ist,j ich=ibuf(i) C C Convert blanks to zeros C if(ich.eq.iblank)ich=izero n=ich-izero if((n.lt.0).or.(n.gt.9)) goto 99 k=k+ipw*n ipw=ipw/10 10 continue iconv=k return 99 iconv=-1 return end �������������lt.0).or.(n.gt.9)) goto 99 k=k+ipw*n ipw=ipw/10 10 continue iconv=k return 99 iconv=-1 return end ������������